Q: Can I use the 40t expander cog with a 36t cassetteA: We don't recommend using the 40t expander cog with a 36t cassette. Shift performance will be compromised as the timing will not be correct.

Q: Can I use the 42t expander cog on my 34t cassette?A: The 42t expander cog WILL NOT work with 34t max cassettes. A 6 tooth jump is the maximum for good shifts.

Q: I have a short cage dérailleur on my bike. Will that work?A: We recommend a medium or long cage dérailleur

Q: Why do you only have a 42t expander cog for SRAM cassettesA: The 40t is available only for Shimano as SRAM is not offering a 34t cassette.

Q: Is it hard to setup the expander cog?A: It's really not too hard, but you are working at the extreme limits of your rear dérailleur. If you have specific questions about the setup and adjustment, we recommend heading to your local bike shop.

Q: I have a really worn drivetrain. Will the expander cog work ok on my bike?A: Old drivetrain components could cause poor shifting performance. We recommend a new chain and a new or well-cared for cassette.

About Cassettes & Freewheels

Cassettes and freewheels for bikes are a cluster of sprockets in a range of sizes offering a multitude of gear ratios. The difference between the two is, a cassette slots onto the freehub, which has the ratchet built in and is then secured with a lockring, whereas a freewheel is a cluster of sprockets built around a ratchet and threads directly on to the hub. Cassettes and freewheels come in many ratios, close ratio is when the number of teeth increase in small increments of 1 or 2 at a time, whereas a wide ratio is when the teeth increase in larger increments of 3 or 4 at a time. Most systems will use a cassette hub as these allow for a wider bearing spacing and increased axle life, you can also fit a larger quantity of sprockets onto a cassette hub with 11 speed systems now becoming available. With cassettes you must use the appropriate spacing for your gear levers and rear mech, Shimano and Campagnolo are not interchangeable so you will need to match the cassette to your levers for smooth and precise shifting. Sram and Shimano chains and cassettes will work together as they use the same spacing.

About the e.thirteen brand

e.thirteen components are a small, rider-owned and operated company which was founded in 2001 by Dave Weagle. Since it inception e.thirteen have always pushed peoples ideas in terms of innovation, function and design and have become a market leader in chain retention systems the world over. e.thirteen have strong roots in competition and they support numerous athletes and events the world over from grassroots racing right up to top flight World Cup competition and World Champions, in fact e.thirteen chain guides and rings have collected more gold medals at World Cup and World Championship competition level in recent years than any other chain retention system, making them the choice for all riders at all levels.

Delivery Information

The delivery options available for shipping this product along with the contents of your basket to United Kingdom are:

International Delivery

Wiggle ships to over 100 countries. To see what delivery options are available for other destinations you can update your delivery destination via the International Options feature at the top right of the website.

Rated 5 out of
5 by
Barns from
It's a handy piece of kit but it's a little priceyI like the range that it gives me. I've also used a one-up and it's similarly good. Nothing beats having the full shimano cassette which has the same range now.

Date published: 2017-05-24

Rated 5 out of
5 by
andkav from
Performs as it shouldThis was a great addition to my cassette. I changed to a bigger chainring as well to move my main riding gear up the cassette to account for the missing 17tooth cog.

Date published: 2017-03-08

Rated 5 out of
5 by
themeek from
High quality, looks good, fits and works well.Bought the Race Face N-W ring and -thirteen Expander Ring at the same time to convert Calibre Bossnut to a 1X chainring.
Both items well made, look great, and work well.
Conversion went smoothly and very happy.
Shifts cleanly, no dropped chains, quiet, simple.
You can buy cheaper but these work like you'd expect.

Date published: 2016-12-09

Rated 5 out of
5 by
PetrusJohansson from
Great productUsed on my Epic Comp Carbon bike 1x10. Easy install and great performance!

Is the 42t cog compatible with all sram cassetes ?

Will this work with a 11t to 36t cassette and also with a triple chainset?

Asked by: yamyam10

So long as it's listed in the compatible cassettes:
http://s.wiggle.co.uk/images/Extended-Range-Cog-Compatibility_C.jpg
It will not work with the 40t well, we advise 42t only with a 36t.
You may exceed the derailleurs capacity with a triple set up and this.